staging: comedi: ni_at_ao: move the boardinfo declaration

For aesthetics, move the boardinfo declaration closer to the struct
definition. Also, remove the cut-and-paste skel driver comment.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>